Many litter boxes are known, especially for domesticated cats who relieve themselves only inside the home of their owner. However, having a cat litter box in the home poses several problems. The odor of cat urine and excrement is particularly pungent and offensive. Many cat owners find the chore of cleaning the litter box inconvenient, time-consuming and repulsive. Handling cat excrement exposes the cat owner to potential health hazards. Furthermore, despite attempts by litter manufacturers to make cat litter which absorbs or masks odors and which is bacteriostactic, nevertheless the litter must still be replaced often to prevent potential growth of bacteria and other microorganisms.
Litter boxes for cats which attempt to reduce the aforementioned handling and odor problems are known. U.S. Pat. Nos. 2,204,416, 3,227,138, 3,734,057, 3,793,988, 3,965,863, 4,196,693, 4,574,735, 4,593,645, 4,729,342, 5,113,801 and 5,289,799 are believed to be representative of the art.
Of the aforementioned patents, only two, U.S. Pat. No. 4,593,645 to Dingler and U.S. Pat. No. 5,289,799 to Wilson, attempt to address the problem of bacterial growth on litter and disposal of litter. Dingler employs a reusable litter which is a relatively heavy, non-porous, non-absorbent type of gravel. The cat excreta and gravel are cleansed by a pressurized stream of water from a spray head which supposedly loosens dried fecal material from the gravel, and agitates the water containing the excreta so that the excreta remains dispersed in the water. After the water has risen to a predetermined level, the cat owner operates a lever to open a valve which rapidly discharges the water containing excreta to a sewer system. It is an essential part of the '645 patent that the gravel is significantly heavier than the excreta dispersed in the water so that the gravel remains at the bottom of the water and is not discharged along with the waste products.
The '645 patent has several disadvantages:
1. The spray of water does not conveniently reach all of the gravel, unless the user hand-sprays the entire litter box, including the bottom gravel. This is time-consuming and cumbersome. PA1 2. Merely spraying the gravel with water does not ensure proper cleaning of the gravel, nor does it ensure that any fecal material clinging or adhering to the gravel will indeed be separated therefrom. PA1 3. The separation of the waste water from the gravel is inefficient because gravel stirred with the water can exit the box together with the waste water and worse, unsuspended fecal material can remain with the gravel, thereby defeating the whole purpose of cleaning the gravel.
Wilson uses an endless belt which conveys soiled litter to a recycler which cleanses the litter. Afterwards, the litter is dried and conveyed to a dispenser for depositing the litter on a surface for reuse.
A disadvantage of the '799 patent, inter alia, is that the conveyor belt and recycler are relatively expensive and take up a lot of space. Furthermore, since the litter is not agitated during cleaning in the recycler, it is difficult to thoroughly cleanse the litter from fecal material clinging thereto.